The invention relates generally to benzimidazole diamine-based polyetherimide compositions and methods for making them.
Polyimides are high-performance materials that are suitable for applications requiring chemical and thermal resistance, and good mechanical and electrical properties. However, fully aromatic polyimides are generally difficult to process due to high softening temperatures and/or solubility. Various approaches have been taken to improve processibility, but they often result in polyimides that suffer in thermal properties. ULTEM, a polyetherimide manufactured by General Electric Company has a good balance of processibility and thermal properties. Commercial grades of ULTEM have glass transition temperatures in the range from about 210° C. to about 225° C., are stable up to about 450° C., and can be processed by injection molding or extrusion. Furthermore, ULTEM polyetherimides have good dimensional stability, mechanical strength, electrical properties, inherent flame resistance, and chemical resistance.
2-(p-Aminophenyl)-5(6)-aminobenzimidazole (also sometimes abbreviated as “ABIZ”) has been used for making polyimides by reaction with 3,4,3′,4′-benzophenone tetracarboxylic anhydride. Copolymers of ABIZ and oxydianiline with biphenyl tetracarboxylic dianhydride (also referred to sometimes as “BPDA”) have also been prepared for achieving high-adhesion polyimides for curl-free copper laminates.
It would be desirable to develop improved polyetherimide compositions that can be used to extend the range of applications over those currently in use. The expanded application areas require the polyetherimides to have higher glass transition temperatures, preferably without losing chemical resistance, thermal properties, and mechanical properties. Such materials are expected to find enhanced utility in the food storage, airplanes, and microelectronics areas.